A lot has changed in the 27 years since Rockford first went mining for diamonds on platforms like the Commodore 64 and ZX Spectrum. Back in 1984, the gravity-defying star of Boulder Dash plied his trade in wonderfully inventive levels, only ever encountered two different types of enemies, and had to work without such modern conveniences as speed boosts and health pickups. Like many other hardworking '80s folk, he also hadn't yet been replaced by a machine. Nowadays, Rockford is the codename used for the BD25 mining robot, which works in levels that vary wildly in quality and are inhabited by all manner of enemies. Equipped with telescopic arms and able to employ various power-ups, the new metal Rockford boasts some improvements over its predecessor. The same can't always be said for Boulder Dash-XL, though, which despite offering more than 150 levels of diamond-collecting and boulder-dodging action rarely re-creates the magic of Rockford's early expeditions.
Boulder Dash-XL feels most like the Boulder Dash games of old when played in Retro mode, a collection of 25 levels that look and play a lot like those in the original C64 game. As Rockford, your goal in each level is simply to collect a specific number of diamonds and then reach the exit within a time limit. You can walk/mine left, right, up, or down, but Rockford's immunity to gravity doesn't mean that you can ignore it. As you move through the dirt, you create tunnels that boulders and diamonds fall into, and one wrong move can result in Rockford getting squished or trapped. Other than movement and the ability to push unobstructed boulders left and right, the only action in Rockford's repertoire is digging one space ahead in any of the four directions he can move in. Sounds simple enough, but you need to get creative to make it through some of the Retro mode levels. You can trap enemies that always turn left (fireflies) or right (butterflies) in tunnel loops if you need to get them out of your way, but in some levels you need to drop boulders or diamonds onto them so that the resulting explosions blast through a wall or create more diamonds, for example. In other levels, the only way to deal with harmless but rapidly multiplying amoebas is to suffocate them so that they turn into diamonds; if left unchecked, amoebas can almost fill entire levels and then, just when you think things can't get any worse, they turn into boulders.
Some of the Retro mode levels use the aforementioned enemies and gameplay mechanics to great effect and present you with interesting predicaments. Too often, though, it's not the level design but the time limit that prevents you from successfully reaching the exit on your first attempt. The time limit is a necessary evil since it's often the only reason that levels are challenging, but it's unfortunate that in most levels your focus is on performing simple actions quickly, rather than on figuring out challenging puzzles. There's an option to play without time limits in Zen mode, but sadly, this option isn't available for any of the Retro levels and can only be used to play through Arcade mode levels that you've already beaten against the clock.
Comprising no fewer than 100 levels, Arcade mode offers a modern take on the Boulder Dash formula with both its gameplay and its occasionally overcomplicated visuals. In addition to including most of the features found in Retro mode (there are no fireflies or butterflies), Arcade mode introduces plenty of new hazards and power-ups--some of them good, some of them not. One neat addition, at least when the level design makes good use of it, is robotic Rockford's telescopic arm. Power-ups are needed to charge it up, but when available, it can be used to grab boulders and diamonds from a great distance, to push boulders that you're adjacent to with enough force to kill an enemy, and to move heavy boulders that are otherwise impossible to budge. Other welcome additions include gates that can be passed through in only one direction, doors that you need color-coded keys to open, and the ability to scroll around the level while simultaneously pausing the action when you're unsure how to proceed. On the flip side, Rockford's health bar (one hit equals game over in Retro mode) and the health packs that you collect to replenish it seem like unnecessary additions; dynamite bundles and the detonators used to trigger them are rarely used in clever ways; and teleporters do little more than let you move between two points in a level without having to do any fun stuff.
New enemies introduced in Boulder Dash-XL run the gamut from slow to speedy and stupid to smart. The only thing most of them have in common, other than being deadly if you get too close to them, is that they appear to be the work of a mad scientist with a penchant for alliteration. Wild walkers, fuzzy flies, radical radiators, dreadful drillers, sinister stalkers, and bold berserkers all threaten Rockford as you progress through Arcade mode, as do fuzzy walkers, trappers, and hoppers. Despite there being so many different types, none of the new enemies are so complex that it takes more than a couple of encounters to figure out what makes them tick, and in time you learn not only how to stay away from them but also how a couple of them can be used to your advantage. Trick a bold berserker into charging at you before you step out of the way, and it might plow right through a row of boulders behind you, for example. Unfortunately, level designs don't always make good use of enemies; baddies slow you down because you have to avoid them, but very rarely do you have to get creative to get past them.
Puzzle mode, on the other hand, demands creative thinking at every step. There are only 25 levels, and most can be beaten in well under a minute, but these diminutive caves offer far more interesting challenges than the larger ones found elsewhere. Some are so small that you can count the number of diamonds and boulders contained within on your hands, but because these items have been placed so fiendishly, figuring out how to collect all of the diamonds and reach the exit might take you numerous attempts. The fact that these smartly designed levels exist makes you wonder why, in Arcade mode, you're occasionally asked to do little more than navigate a twisting path of diamonds like you're inside a maze in which all of the incorrect routes have been walled off. Completing all 100 Arcade levels isn't easy by any means, but both the difficulty and the quality of the level design are so inconsistent that you might be left wondering if all of those levels were really necessary.
You get a lot of game for your money when you spend 800 Microsoft points on Boulder Dash-XL, but not all of the game's 150-plus levels are good. It's true that even some of the weaker levels might offer some lasting appeal if you get competitive on the online leaderboards and try to perfect your routes through them, but those that aren't fun the first time still aren't much fun 20 runs later. And besides, the dedicated Score Attack mode is a better way to compete online, because its levels (of which there are only four, sadly) are designed to be much less linear than those in the Arcade and Retro modes. Boulder Dash-XL is great when it sticks close to the original Boulder Dash formula, but an apparent focus on quantity rather than quality hurts the experience. Where the original Boulder Dash was a true diamond, Boulder Dash-XL is merely a convincing cubic zirconia.