Aren't (weren't) 88mm flaks a high altitude gun? Don't they have a minimum effective range? Don't IL-2s, and most aircraft for that matter, fly predominantly below that minimum range?
wrongway
Exactly.
I think many players do just have our 5" ship guns in mind when it comes to the 88 Flak.
The first and biggest difference is - the 88 had no proximity fused shells. They had timed fuzes, which were (in the field) mostly set according to distance estimation by optical instruments or (mostly on the homefront, or behind frontlines) by radar readout. That's
much less accurate than our point-n-shoot proximity fuses.
The 88 (and other heavy flak guns) were used against targets cruising at altitudes or shooting barrages at predeteminated altitudes. It was not a very efficient weapon against fast & maneuvering targets on the deck, which is what our Il-2's do almost exclusively. (In real live they would often travel in formations at higher altitudes, being again targets for heavy flak). The weapons of choice against
Tiefflieger - low level bombers and Jabos - were light & medium flak guns: Mostly 20mm & 37mm. When those proved themselves as not capable enough, 50 & 55mm flak guns were developed.