this is partly the same game but with alot of new addons but i shouldn't call them addons because they are more than that.
If you have played the first one than you will might find this in the beginning very,very fimmiliar but then you start to see more new things like a new background or level name for instance instead of (Basement)you get(Cellar)
however that isn't the only difference in this game there are alot more poweups than expected (for me atleast) and some new bosses and a door that gets one heart everytime you pass through it and there are three new levels.
So gameplay hasn't really changed much for this game which was alright for me as for the difficulty it is still hard as ever if you die you go all the way back to the beginning of the game which can be a little frustrating but the game isn't exactly long to begin with but will have playing for hours and hours so it kind'a makes since that you start from the beginning but it can get on your nerves a bit.
There are some new soundtracks for different levels which i liked since the original soundtrack was awesome.
If you have never played (The binding of Issac) than this is a good place to start.this game will keep you focused and playing for a long time and there is replay values because there are random bosses as well as random level mapping and a hidden level with SIX ENDINGS.
I highly recommend this game for people who want a change of pace from everything that you see these days and have alot of spare time.