Tweaks

Block process priority class	BLOCKPRIORITYCLASS	Blocks a process's attempts to change its own priority class. Old fullscreen games may use this trick to get 100% CPU power dedicated to them, but on modern OSes and windowed environments this could be a bad idea, interfering with other operations and overheating the processor for no reason.
Set single core process affinity	SINGLEPROCAFFINITY	Some games are not properly synchronized to run on physically separate multiple core CPUs, or simply don't properly handle powerful CPUs. This option sets the program's core affinity so that the program is run by a single core (the first one).
Set last core affinity	USELASTCORE	Same as SINGLEPROCAFFINITY, but picks the last CPU core.
Limit available resources	LIMITRESOURCES	Causes the query for available resources (RAM, hard disk space, and so on) to return a limited value: some old games can't handle a very big integer number and see it as a negative value, refusing to start.
Disable performance counter	NOPERFCOUNTER	Since performance metrics hardware is not mandatory on a PC, this flag disables the GetPerfCounter() performance metrics API, simulating an unsupported condition. Usually, in this condition the software should rely on other performance measurement metrics that are more conveniently manipulated by DxWnd timing hooks. It should be set when, despite the time acceleration feature, the program doesn't seem to behave according to the imposed speed ratio.
Bypass font unsupported api	FONTBYPASS	Some games may attempt to manage old font styles that were present by default on legacy platforms and are no longer supported. This flag simulates a success operation to let the program continue. Of course, the font will be wrong, but Windows will approximate the choice with the most similar available font.
Replace privileged opcodes	REPLACEPRIVOPS	Real multitasking OSes (from Windows NT onward) forbid applications from using privileged instructions that directly manipulate the hardware, like the IN opcode. Running a program with such opcodes would result in a program exception on modern systems. This option scans the program code segment at startup and replaces all detected privileged operations with NOP (no operation) instructions. Since these opcodes are often dedicated to interactions with sound hardware, the program will likely work with the possible side effect of some audio issues. Use this flag for games like Ubik.
Suppress IME	SUPPRESSIME	The flag tries to suppress IME windows. This feature is not yet fully functional.
Handle exceptions	HANDLEEXCEPTIONS	Setting this flag causes DxWnd to set its own exception handler that tries (often successfully) to fix several common exceptions, such as the divide by zero exception in old games that were trying to calculate the CPU speed.
Diablo tweak	DIABLOTWEAK	A flag that seems to improve Blizzard's "Diablo" compatibility. It should not be used for other games and will cease to be supported as soon as a more general tweak is discovered.
Intercept Imagehlp.dll	NOIMAGEHLP	Intercept imagehlp.dll unsupported calls, returning a clean error condition so that the program doesn't crash. One notable game that needs this flag is The Fifth Element.
EA Sports hack	EASPORTSHACK	Intercept and neutralize some of the internal hooks usually set by "EA Sports" games, and possibly other titles as well.
Reserve legacy memory segments	LEGACYALLOC	Old 16-bit programs for Windows 95 and 98 relied on the availability of memory from address 0x4000000 to 0x8FFFFFF, even though they never explicitly allocated it. Recent OSes don't guarantee this memory availability. This flag, combined with DLL injection, reserves memory in this range when the program starts up, before that memory can be used for other purposes.
Disable Max Windowed Mode	DISABLEMAXWINMODE	Invoke DirectDraw SetAppCompatData(12,0) to set the DisableMaxWindowedMode.
Disable "disable Alt-Tab"	DISABLEDISABLEALTTAB	Disable the compatibility patches that disable the Alt-Tab key combination to avoid window switching, along with other similar key combinations. Usually, programs hooked by DxWnd can afford window switching with no impact, either by default or by setting the UNNOTIFY flag.
Win7 color fix	COLORFIX	As described in a DirectDraw hack, this flag fixes a color problem that Windows 7 has with 8BPP palettized modes. It only has an effect when the screen is actually set to an 8BPP color depth, which is now very rare.
Fix GlobalUnlock	FIXGLOBALUNLOCK	Fixes a reported problem of the 16-bit GlobalUnock() API's 32-bit port. In some cases, it never returns the expected value, causing game crashes or endless loops.