Excellent game, sir!
This game is truly amazing. The detail, the physics, the complete harmony of everything going together! I especially love how you can personalize the character. You have done a great job with this.
In the sequel, you can consider having a volume option too - I like to listen to music while I play the games and gunshot sounds can innundate the eardrums.
Also, in addition to the weapon scroll forward key "E," how about a weapon scroll backwark key "Q"? It would be helpful.
_____________TIPS_________________
-The keycard is on a platform in the middle of the level.
-To open the keycard door, just walk into it, facing it and it will raise itself.
-You get weapons for completing levels.
-You get a weapon for Overkilling - killing above a certain number of enemies in both levels and survival modes.
-You can find weapons hidden in most large story mission level maps.
-Duck and enemies' bullets have a lower chance of hitting you.
-Weapons with slower rates of fire do not become useless as time goes on; especially with machine guns and automatic assault rifles, slower firing rates can suppress an incoming hoard with a wall of bullets at a constant rate all the while saving ammunition. This principle works well in survival modes like Stinky Bean and Zombies.
-The bonus weapon you get for Overkilling on the last story mission level is in my opinion the best. It is extremely powerful, and (in cases of everything except zombies and bosses) kills in one hit. It also has an added splash damage bonus.
-Replay as you accumulate more powerful weapons. The game will become increasingly fun and easy!