I'm a big fan of the Munchkin series. There are a ton of themes and they mostly work well with each other. For example, you can get the base deluxe edition and buy Space Munchkins and play them together. Although for this one I don't recommend doing that.
Munchkin is a monster fighting game for up to six people. It plays best with 4+ players but we frequently play it with only three.
There are probably 20-30 different themes for the Munchkin series, and so far this is my favorite. We currently own three different versions and two of them we have mixed and play as one.
This version mixes the older TMNT turtles with the Munchkin rule game. I wish it was using the newer Nickelodeon series of turtles.
The artwork on the cards is good quality and interesting.
The original game was pretty funny and downright goofy at times.
This version is a bit more serious.
The game plays on a board that tracks your progress from level 1 to level 10.
As you defeat monsters (or get level up cards) you raise up in level. Harder monsters will give you more treasure and potentially more levels.
Your character can equip weapons and armor to increase their level and potentially get unique bonuses. Combined with the level you are on the board is how much damage you can do in combat.
Turns start with kicking open the door which may result in a monster fight, trap, or ability cards. If you run into a trap or a monster when you open the door you have to resolve this. You can ask for help in exchange for some of your loot with other players but if you lose you may lose all your gear. Weaker monsters have smaller penalties for losing.
Initially, you will find players willing to help each other, but as you get further into the game players will turn on each other. In fact, another player can play a trap on your turn to hinder your progress or make a fight more difficult. Other players can actually play another monster against you as well if they have a special ability card that allows them to do that.
After you resolve the first round of kicking open the door, you can do two things. You can "loot the room" and pull a card from the treasure pile or "look for trouble". If you did not fight a monster when you kicked open the door you are allowed to look for trouble. This allows you to take a monster card you got previously and fight it directly.
Some of the cards are weapons and armor but you can also get sidekicks that help you out by providing a damage boost and potentially protect you from death.
You can also sell loot to level up, you need at least $1000 worth of items per level.
Once someone reaches level 10 (by fighting a monster, you cannot use a level up card or sell loot for the final level) they win.
From what I hear, there are some expansions coming out for the game as well.
You can find the game on Amazon for $21.54 shipped. I highly recommend the Deluxe edition as it comes with the playing board.
If you own other versions of Munchkins the boards are usable but I like to have the full TMNT experience with the custom board and it is only a few dollars more.
You can check out my original review of the base Munchkin game.