This is a faithful and accurate recreation of the original game. All the SimTower code has been rewritten from scratch, but the original game assets such as images and sound need to be loaded from the 1994 release.
Insert your own copy of SIMTOWER.EXE, or the compressed SIMTOWER.EX_. This page will parse it locally, extract the assets, and let you play the game. Nothing is uploaded to a server (besides a few analytics shown here).
Where do I find SIMTOWER.EXE?
No copy? Search the web for “SimTower download”. The game hasn't been sold since the 90s and preservation archives keep it; takes a minute. You'll get a ZIP or a CD image. Open it (7-Zip handles both) and load either SIMTOWER.EXE or SIMTOWER.EX_ from inside. Either works here as-is.
Installed folder? Load SIMTOWER.EXE, about 6 MB.
CD or CD image? The disc has it compressed as SIMTOWER.EX_ (underscore). Load that directly; this page unpacks it.
Floppies? Disks 2 and 3 hold SIMTOWER.E1_ and SIMTOWER.E2_. Select both at once.
Windows releases only (1.0 and 1.1b). The Mac version won't work.