Based on the pieces in the photo is looks like the remains of set# 4957 Ferris Wheel.
They had apparently built one of the secondary/alternative models from the set.
(Building instructions here: https://www.lego.com/en-us/service/buildinginstructions/search#?search&text=4957)
These pieces are from Mega Bloks "Warriors: Future Force" set# 9528 "U-240 Assault".
Even though the picture is low resolution, you can see the orange parts on the three barrel turret better:
The shirt itself says 1998 on it, which coincides with the earliest known release of a set for that theme.
Here it is advertised on/in this 1999 January/February issue of Lego Mania magazine:
Given this was advertised at the very beginning of 1999, I think it is safe to assume that ...
The Jungle Adventurers sets were released in 1999, and it seems likely that it would be released that same year. The full design below shows this is the Adventurers line it corresponds to.
There is a copyright on the design, which turns out to be 1998, but it likely predates the actual release which seems to have been in January 1999.
Seems to be mostly from one set with a mixture of Minifigs and accessories.
Set #10195-1 Republic Dropship with AT-OT. (Referencing your picture, these are generally the bricks below your Minifigs.)
Some Minifigs and accessories.
Set #8084-1 Snowtrooper Battle Pack. (Referencing your picture, some of your Minifigs come from this set.)
Headgear: Part ...