If I remember right, this game works great on Dosbox. Anyone who's never heard of it should give it a try.
Eh, about not being able to tell their size, it's true that it could just as easily be people fighting, but there's something so wonderfully satisfying about the metal smashing sounds this game has.
Advice: resist the urge to buy equipment that you can't very easily afford. If you lose the next fight, your mechanic might have to sell it off. SUCKS ASS when a 7,800 armor upgrade has to be sold to pay for 300 in repairs.

Also, while upgrade kits will be sold if you buy a new mech, skill upgrades never go away (except in rare circumstances...). The best time to invest in skill upgrades is ALWAYS! Never buy the Nova. It is the crappiest piece of crap ever.
My favorite mech was the Shadow, for the back/kick and back/punch moves. Jaguar was really good too for it's down/back/punch, that'd throw your opponent across the arena FOR MASSIVE DAMAGE!
Eh... I think I preferred the shadow though. Very versatile with a lot of badass moves.