Good for short sessions but not much depth. Fairly fun for the price-tag. Creative as a puzzle-type game.
The bad: Time-attack mode can be very tedious, narrow game-play means short sessions (good & bad)
Mr. Driller for PS1 and Dreamcast is a very addictive game. It's fairly simple: you're city is attacked by an abundance of colored blocks. You job is to drill down to their source underground without being crushed or running out of oxygen.
As you journey down a tunnel, you must watch out for falling blocks and snag oxygen tablets. Getting crushed or suffocating will cost you one life. Your job is to drill down to a depth of 5,000 (on easy [10,000 on hard]) to win the game and find out the mystery of the source of the blocks.
My introduction to this game was from a friend with a Dreamcast. A group of friends of mine would take turns seeing who could get the farthest. The game is primarily a single-player game. It's simple but engaging. It's definitely more challenging than the Bejeweled type games but easy to pick up.
The Time-Attack mode offers something for players who beat the Arcade mode. In Time-attack, you have to do a nearly perfect run to make the time requirement. Time-attack can be frustrating because you'll be playing the same level over and over until you find out the perfect sequence of blocks to break.
For what this game would cost you to pick up a PS1 version of the game, it's probably worth it. You wouldn't even need a PS1 now that there are good emulators on hand from the Internet. I have a PS1, but I went for the Xbox 360 so I can't play this on a PS3 or anything.
I noticed from a google search that this game is now on the iPhone and Nintendo DS. I'm not sure if these later games live up the original. The only versions I've played are the Dreamcast and PS1 versions of the game.