If I had to recommend something, I'd definately request these:

:arrow: Network play! LAN or TCP/IP would be easier to get friends to play against.

Plus two people on one keyboard... You'll run into issues with the other person holding keys or registering someone elses key instead of yours... I had a game I made that used this type of control and this was a major issue that people mentioned to me.

:arrow: Joystick/pad control, also a solution to the two people, one keyboard issue. Besides joypads are just... cooler! I love my Madcatz XBox style controller, but it never gets enough use. :?

:arrow: When your best friend is kicking your butt he wants to see it! A score or frag count should be there to keep the story straight in case of "I'm winning!" "No, I'm winning!" debates.

:arrow: Maybe a tiny indicator for what upgrade is active for what player? Could go under the frag count/score label.

AFTER PLAYING

:arrow: Number of rounds! Allow the option ot set number of rounds and have a "Round One" announcement or something. This will help for keeping score and keeping the gameplay going without having to mess with menus in between and such.

:arrow: End Match Stats! Some players LOVE this. It shows neat little tally of what kind of players they are. It also makes the game seem smart that it can size up it's players too. And people generally like to use these values to compete against others aswell.

:arrow: If you had some AI and the NET/LAN feature I'd recommend a tournoment mode of play. Sort of like elimination.

:arrow: High scores stored. Take say the top 10 scores and have players store their names from games played locally and on a NET/LAN game. Some developers like to seperate these into NET/LAN and LOCAL, but I say just put 'em in together. If you like you can use an icon to indicate the difference. Maybe it's the player/team's sybmol or flag too? Like in Worms.

:arrow: Yeah definately wider rope detection, but also... maybe be able to grab and start climbing ropes while jumping? Would help to be able to jump out of an enemy's weapon aim and onto a nice safe rope.

:arrow: Maybe it's just my computer but the running seemed a tad slow. Then again I alteredthe settings by hitting default so this may be my fault. :?

:arrow: A far-out idea, but definately for NET/LAN/AI play, 3+ rumble and co-op team play... On ship my mess mates[size=9px](a mess on a ship is like a room with bunks and a lounge area for us when we are not on watch(working ))[/size] have an N64 and all we do sometimes is play Mario Cart 4 player... You'd be supprised how much fun we all have. There is often 3 to 4 playing at once. More friends equals more fun, I say!

Other than that, I love the different moves the guys can do to run jump and roll out of the way of an attack. Nicely done!