It was a full playable game last I checked, but it has been a while. WZ2100 was unique old RTS - instead of having predetermined units, you get chassis, mobility elements and weapons. You form unit designs from combination - Cannon + Heavy Body + Treads for a tank, Machine Gun + Light Body + Rotor for a support copter. Can make hover tanks, bombers, all sorts of nifty stuff.
Had a per unit xp system too - very high cap. It actually ended up mattering too - you could retire an experienced unit, and then the next unit you build would inherit their XP level. That way, you didn't end up with veterans that were obsolete.
Never did beat it though - it gets brutal on the later stages of the campaign even on the easy difficulty setting.