* using 384 horizontal lines of resolution is a hack that, as far as I know, was never used in any games. I suspect something like Sonic 2's split screen 2 player mode could be done.
** 4, 16 and 256 color modes are the only practical modes used by AAA games (and 256 is very rare). But any of these modes can select from the 4096 color palette and the palette can be swapped per scan line and per frame (about 15 fps maximum if such hackery is used). Each scan line, however, was limited to having a maximum of 16 total colors. Most games stick to 16 colors and use 320x200 mode if they use more colors than that. 256 colors can be used at 60fps in very limited circumstances (such as a scrolling banner). The KEGS emulator is the most accurate IIgs emu, but it fails to reliably duplicate anything more than 256 color graphics.
The IIgs retailed for $999. Later upgrades to the system, such as 768KB to 1MB RAM, improved video card, and ROM upgrades did not alter the price.
After Steve Jobs was ousted from Apple, Jean-Louis Gassée had the job of designing new models of the ][gs. Along with an engineer, he worked on two designs. The Apple IIsi "Centossa" was a design with a built-in 3.5 drive on the right side of the case. The Apple IIgs+ "Mark Twain" was similar but also included a hard drive and the 3.5"drive was on the left of the case. No other improvements. In fact, since the internal hardware blocked upgrade slots (IIgs slots in the Centossa, legacy slots for classic Apple II hardware in the Mark Twain) it could also be thought of as a streamlined downgrade. Centossa never left the planning stage but a mockup was created. Mark Twain units were created and this product was set to be announced in September 1991. But at the last moment, someone in marketing noticed that demand for the Mark Twain was expected to be 70,000 units. Apple still had 70,000 unsold Macintosh LC units (Apple Lisa computers with a Mac label on them). So, it was concluded, somehow, that sales of the Mark Twain, despite being a vastly different computer from the LC and real Macintosh computers, would cannibalize LC sales and thus the Mark Twain could not be be brought to market.
Vtech announced the Laser 128gs for under $600 in 1988 (double the price of the Apple ][ compatible Laser 128). But, this never seems to have been released. Possible because the various Apple ][ models were completely off-the-shelf parts clearly identifiable on the board with only the ROM chip and data to be studied (or not, the ROM data could actually be purchased from Apple at the time). The Laser 128 was basically a 1:1 hardware copy with no improvement, variation, or cheaper parts (just identical parts on an identical board); a fact that irritated Steve Wozniak who angrily announced to Vtech at CES, "I'm your chief hardware engineer!". Their response of, "Yes", prompted Woz storm off thinking he'd gotten a Pyrrhic victory. Later he would lament that he should have demanded a salary. But, the IIgs had 8 custom chips that would have required reverse-engineering (which was not Vtech's greatest skill). This would have taken time and expense in the small and shrinking Apple ][ market that the IIgs had done little to expand; or different sound and video hardware at the very least and a solution to software that expected the original hardware.