that's because its a heavyweight ;P
ironforge weightclasses are a little weird, MW is 200kg and HW is 400kg, not counting ballasts. unfortunately we are unable to reprogram the game to change the weightclasses, so the best we can do is just remember what the weights are.
it's not a bad bot. you're on the right track. I'd recommend using a weaker weapon motor to save weight (you don't need a very powerful one on a shell spinner) and use stronger motors for the drive. Your batteries are technically fine, but you may want to use a car battery in there + another battery to get it up to 30 amps, it will last much longer than these energizer ones.
The main thing you probably want to work on though is your weapon placement. combinations of different weapon types and sizes is hard to do effectively in RA2, especially in the ironforge mod. in Ironforge, the weapons generally only do damage on the sharp parts, and it usually tells you this in the component descriptions in game. You've lined up all your weapons correctly except the iron spikes, which only do damage on the tip meaning they are not being utilized in this setup. while the crushing teeth are facing the right way, their placement here means they will generally not hit the opponent since they are not as long as the knives beneath. the knives are really the only things doing damage right now, meaning half of your entire weapon setup is not being utilized. It's very easy to fix though, just find some uniform weapons and try to use them all along the shell.
also try to post what armor type and thickness the robot has, it helps us a lot. You also probably want to rename your showcase something like "THBQ's showcase" to avoid confusion.
good first bot man, and welcome to the forums. I'll be glad to see what else you come up with :)