I have just installed and tried the game after reading your message. I used the closest machine to yours that i have now, which is a K6-III 400 with ATI Rage 128 Pro and Windows 98 SE. Apparently the game runs fine on me, it seems to be smooth enough and quite playable at 640x400, the only resolution i tried (though the control system is not the best one ever).
What's your configuration? This is mine, just for comparison purposes:
HARDWARE
MOB: Lucky Tech P5MVP3 (VIA MVP3 chipset)
RAM: Kingston 1x DIMM 256 Mb PC133 SDRAM
CPU: AMD K6-III 400 Mhz
VGA: ATI Rage 128 Pro AGP 4x
NIC: Realtek RTL8029AS PCI
SND: Yamaha YMF719-S ISA
HD1: Fujitsu MPD3064AT UDMA66
HD2: Maxtor 90640D4 UDMA33
CDR: Lite-On LTN483L 48x
CONFIG.SYS
DOS=HIGH,UMB
device=C:\DOS\himem.sys
device=C:\DOS\umbpci.sys
devicehigh=C:\DOS\vide-cdd.sys /D:IDECDROM
devicehigh=C:\WINDOWS\COMMAND\display.sys con=(ega,,1)
Country=034,850,C:\WINDOWS\COMMAND\country.sys
Shell=C:\COMMAND.COM C:\ /P /E:512
AUTOEXEC.BAT
lh C:\DOS\mode con codepage prepare=((850) C:\WINDOWS\COMMAND\ega.cpi)
lh C:\DOS\mode con codepage select=850
lh C:\DOS\keybsp
DOSSTART.BAT
LH C:\DOS\MXK6OPT
LH C:\DOS\CTMOUSE
LH C:\DOS\SHSUCDX /D:IDECDROM
C:\DOS\SETUPSA /S
SET BLASTER=A220 I5 D1 T4
By the way, Delphine software's DOS games have always run very badly under Windows 9x (even old DOS version of Another World/Out Of This World crawls when played in a command window). Make sure that you are running the game under pure DOS, either not booting into Windows 98, or restarting in MS-DOS mode before launching the game. Hope this helps.