Finally completed the final level, which ended up being the third one. Didn't get as many levels as I orginally wanted, but I guess there's a limit to how much you can do within a month, especially if you need to take care of tons of other stuff as well.
Anyway, the game now features 3 levels, and about 20 different enemies.
If you don't die at any point, the levels take around 3 to 5 minutes to complete. But since you will of course not avoid dying, the actual amount of gameplay will probably be somewhat longer. I probably went slightly overboard with the last level in terms of difficulty, and lacked the time to make it simpler.
I also implemented a level select menu which you can access everytime you load the game, so that you can choose from what level you wish to play, as long as you've reached the level in question. Doing this will give you the score and weapon you had when you finished the level prior to the one you choose. This probably seems a bit trivial since there are only 3 levels anyway, but I wanted to implement it from the start, so I did.
I also added a simple intro and ending, with the intro including some of my less than flattering pixel art:
This is Captain Mutty, calling RAD DOG for help against the evil MAD CATS.
The is complete and can be played from start to the end, but it will very likely lag on older computers, so I will still try to look for a few ways to optimize the code and possibly add some way to reduce it. The problem is that fixing the lag will probably require sacrificing accuracy of the hit detection. Unless I find some magic bad code I've overseen, I'll probably try to add some option menu where you can adjust the balance between lag and hit detection in the future.